Administration of postoperative analgesia following abdominal surgery is complicated by analgesic adverse effects such as sedation, nausea, and postoperative ileus. Intravenous lidocaine infusions for postoperative pain previously have been shown to be beneficial at decreasing pain, reducing opioid requirements, and hastening return of normal bowel function, noted Mark E. Schroeder, MD, of the University of Wisconsin Hospital & Clinics, Madison, WI, and colleagues. This study examined the outcomes of providing continuous perioperative lidocaine infusions, in the course of routine perioperative care, to adults who underwent an abdominal visceral operation.

Between February 2011 and April 2012, they recruited 117 adult postoperative patients from a 471-bed hospital in the Midwest. Inclusion criteria were age >18 years, English or Spanish speaking, and being alert enough to respond. Anesthesiologists identified appropriate patients and injected an initial bolus of 1.5mg/kg lidocaine IV followed by a continuous infusion of commercially prepared lidocaine (2gm/500mL) at 2.33mg/kg/hr, which was run for the duration of the operation. “On arrival in the recovery room, the infusion rate was decreased to 1.33mg/kg/hr and continued postoperatively on the inpatient unit until the bag was completed,” they reported.

Study outcomes were measured using patient surveys and medical record audits of treatment administered pre-, intra-, and postoperatively. Measures included time spent in severe pain, percent pain relief; interference from pain on activity, sleep, and emotional wellbeing; side effects of treatment; patient satisfaction; and opioid consumption over the first 24 hours postoperatively.

Analysis of the data on 35 matched pairs found no statistically significant results for any primary outcomes, including pain, percent of time spent in severe pain, pain relief, total opioid consumption, side effects or patient satisfaction, Dr. Schroeder noted. “Contrary to published studies, there was a (non-statistical) trend of lidocaine patients to consume more opioids.”

Side effects—including nausea, drowsiness, itching, and dizziness—were present in both groups but were generally reported as mild and no significant adverse events were noted; in addition, no lidocaine infusion was stopped due to presumed systemic toxicity.

“This study adds information about the clinical feasibility, safety, and advantages of administering continuous lidocaine infusion as part of a multimodal analgesic regimen for visceral operations,” he concluded. The lack of differences may be due, in part, to the small sample size; further study is warranted.